The field of the invention is in the structure of primary and secondary batteries and more particularly in battery deactivation structure to prevent thermal runaway and explosions.
Frequently due to the breakdown or maladjustment of other equipment the electrical load placed on a battery becomes greater than the designed amount. If the overload is exceedingly large, circuit breakers or fuses in some application will operate to remove the load from the battery, however, in many applications, particularly where normally high currents are passed for only relatively short periods of time no circuit breakers or fuses are in the system. The connection of the starting motor to the battery in an automobile is a typical example of this. In some instances batteries become internally defective and produce hot spots and thermally runaway due to internal defects and shorts with normal external loading. In some installations it is of no great consequence if a battery overheats or explodes. In many applications, particularly where the battery is inaccessible, or where serious other consequences would result from an explosion such as when batteries are used in satellites, space ships and aircraft, it is extremely desirable to prevent a battery explosion. Also, it is frequently very desirable to maintain some source of energy, even though reduced, after a battery has been damaged by an overload or an internal defect.
Prior art means of internally controlling the temperature of batteries is exemplified by U.S. Pat. No. 3,837,918 to patentee Nakabagashi, and 3,880,670 to patentee Shinn.